// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Chen-Pang He <jdh8@ms63.hinet.net>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_SELFADJOINT_PACKED_PRODUCT_H
#define EIGEN_SELFADJOINT_PACKED_PRODUCT_H

namespace internal {

/* Optimized matrix += alpha * uv'
 * The matrix is in packed form.
 */
template<typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjLhs, bool ConjRhs>
struct selfadjoint_packed_rank1_update;

template<typename Scalar, typename Index, int UpLo, bool ConjLhs, bool ConjRhs>
struct selfadjoint_packed_rank1_update<Scalar, Index, ColMajor, UpLo, ConjLhs, ConjRhs>
{
	typedef typename NumTraits<Scalar>::Real RealScalar;
	static void run(Index size, Scalar* mat, const Scalar* vec, RealScalar alpha)
	{
		typedef Map<const Matrix<Scalar, Dynamic, 1>> OtherMap;
		typedef typename conj_expr_if<ConjLhs, OtherMap>::type ConjRhsType;
		conj_if<ConjRhs> cj;

		for (Index i = 0; i < size; ++i) {
			Map<Matrix<Scalar, Dynamic, 1>>(mat, UpLo == Lower ? size - i : (i + 1)) +=
				alpha * cj(vec[i]) *
				ConjRhsType(OtherMap(vec + (UpLo == Lower ? i : 0), UpLo == Lower ? size - i : (i + 1)));
			// FIXME This should be handled outside.
			mat[UpLo == Lower ? 0 : i] = numext::real(mat[UpLo == Lower ? 0 : i]);
			mat += UpLo == Lower ? size - i : (i + 1);
		}
	}
};

template<typename Scalar, typename Index, int UpLo, bool ConjLhs, bool ConjRhs>
struct selfadjoint_packed_rank1_update<Scalar, Index, RowMajor, UpLo, ConjLhs, ConjRhs>
{
	typedef typename NumTraits<Scalar>::Real RealScalar;
	static void run(Index size, Scalar* mat, const Scalar* vec, RealScalar alpha)
	{
		selfadjoint_packed_rank1_update<Scalar, Index, ColMajor, UpLo == Lower ? Upper : Lower, ConjRhs, ConjLhs>::run(
			size, mat, vec, alpha);
	}
};

} // end namespace internal

#endif // EIGEN_SELFADJOINT_PACKED_PRODUCT_H
